Design theory and vibration characteristics of a contact head slider

Abstract

In this study, the design theory of a previously proposed contact head slider was extended by considering a thermally protruding head slider and the intermolecular adhesive force between the head and disk surfaces. The waviness-excited vibration characteristics of the thermally protruding contact head slider were analyzed using a single-degree-of-freedom slider model, whose contact stiffness was calculated in accordance with the Johnson–Kendall–Roberts adhesive contact theory. It was found that, because of the adhesive force, the resonance frequency fr of the contact slider changed from zero to a value higher than the original second-pitch-mode resonance frequency with an increase in the head-penetration depth. Because the waviness-excited vibration of the contact slider is amplified at fr, the first- and second-pitch-mode vibrations of the thermally protruding slider can be excited when fr approaches those resonance frequencies. Because the friction force varies with the vibration of the contact slider, vibration modes of the slider-suspension system often observed at the beginning of contact can be explained. It is suggested that the region of the head-penetration depth for perfect contact sliding can be widened by increasing the effective contact damping and decreasing the disk waviness.